package com.study.common.util;

import java.net.InetAddress;
import java.net.UnknownHostException;

import javax.servlet.http.HttpServletRequest;

/**
 * ip工具类
 */
public class IpUtils {
    public static String getIpAddr(HttpServletRequest request) {
        if (request == null) {
            return "unknown";
        }
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("X-Forwarded-For");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("X-Real-IP");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }

        return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : ip;
    }

    public static boolean internalIp(String ip) {
        byte[] addr = textToNumericFormatV4(ip);
        return internalIp(addr) || "127.0.0.1".equals(ip);
    }

    private static boolean internalIp(byte[] addr) {
        if (StringUtils.isNull(addr) || addr.length < 2) {
            return true;
        }
        final byte b0 = addr[0];
        final byte b1 = addr[1];
        // 10.x.x.x/8
        final byte SECTION_1 = 0x0A;
        // 172.16.x.x/12
        final byte SECTION_2 = (byte) 0xAC;
        final byte SECTION_3 = (byte) 0x10;
        final byte SECTION_4 = (byte) 0x1F;
        // 192.168.x.x/16
        final byte SECTION_5 = (byte) 0xC0;
        final byte SECTION_6 = (byte) 0xA8;
        switch (b0) {
        case SECTION_1:
            return true;
        case SECTION_2:
            if (b1 >= SECTION_3 && b1 <= SECTION_4) {
                return true;
            }
        case SECTION_5:
            switch (b1) {
            case SECTION_6:
                return true;
            }
        default:
            return false;
        }
    }

    /**
     * 将IPv4地址转换成字节
     * 
     * @param text IPv4地址
     * @return byte 字节
     */
    public static byte[] textToNumericFormatV4(String text) {
        if (text.length() == 0) {
            return null;
        }

        byte[] bytes = new byte[4];
        String[] elements = text.split("\\.", -1);
        try {
            long l;
            int i;
            switch (elements.length) {
            case 1:
                l = Long.parseLong(elements[0]);
                if ((l < 0L) || (l > 4294967295L)) {
                    return null;
                }
                bytes[0] = (byte) (int) (l >> 24 & 0xFF);
                bytes[1] = (byte) (int) ((l & 0xFFFFFF) >> 16 & 0xFF);
                bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                bytes[3] = (byte) (int) (l & 0xFF);
                break;
            case 2:
                l = Integer.parseInt(elements[0]);
                if ((l < 0L) || (l > 255L)) {
                    return null;
                }
                bytes[0] = (byte) (int) (l & 0xFF);
                l = Integer.parseInt(elements[1]);
                if ((l < 0L) || (l > 16777215L)) {
                    return null;
                }
                bytes[1] = (byte) (int) (l >> 16 & 0xFF);
                bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                bytes[3] = (byte) (int) (l & 0xFF);
                break;
            case 3:
                for (i = 0; i < 2; ++i) {
                    l = Integer.parseInt(elements[i]);
                    if ((l < 0L) || (l > 255L)) {
                        return null;
                    }
                    bytes[i] = (byte) (int) (l & 0xFF);
                }
                l = Integer.parseInt(elements[2]);
                if ((l < 0L) || (l > 65535L)) {
                    return null;
                }
                bytes[2] = (byte) (int) (l >> 8 & 0xFF);
                bytes[3] = (byte) (int) (l & 0xFF);
                break;
            case 4:
                for (i = 0; i < 4; ++i) {
                    l = Integer.parseInt(elements[i]);
                    if ((l < 0L) || (l > 255L)) {
                        return null;
                    }
                    bytes[i] = (byte) (int) (l & 0xFF);
                }
                break;
            default:
                return null;
            }
        } catch (NumberFormatException e) {
            return null;
        }
        return bytes;
    }

    public static String getHostIp() {
        try {
            return InetAddress.getLocalHost().getHostAddress();
        } catch (UnknownHostException e) {
        }
        return "127.0.0.1";
    }

    public static String getHostName() {
        try {
            return InetAddress.getLocalHost().getHostName();
        } catch (UnknownHostException e) {
        }
        return "未知";
    }

    // ipIsValid("192.168.1.1-192.168.10.10,192.168.1.5", "192.168.2.4") true
    public static boolean ipIsValid(String ipSections, String ip) {
        for(String ipSection : ipSections.split(",")) {
            if(ipSection.contains("-")) {
                int idx = ipSection.indexOf('-');
                
                String[] sips = ipSection.substring(0, idx).split("\\.");
                String[] sipe = ipSection.substring(idx + 1).split("\\.");
                String[] sipt = ip.split("\\.");
                long ips = 0L, ipe = 0L, ipt = 0L;
                for (int i = 0; i < 4; ++i) {
                    ips = ips << 8 | Integer.parseInt(sips[i]);
                    ipe = ipe << 8 | Integer.parseInt(sipe[i]);
                    ipt = ipt << 8 | Integer.parseInt(sipt[i]);
                }
                if (ips > ipe) {
                    long t = ips;
                    ips = ipe;
                    ipe = t;
                }
                return ips <= ipt && ipt <= ipe;
            } 
        }
        return false;
    }
}
